Control for wireless receiving sets and other electrical apparatus



April 16, 1929. L 1 799374 CONTROL FOR WIRELESS RECEIVING SETS AND OTHER ELECTRICAL APPARATUS Filed.'Nov. 15, 1924' 4 Sheets-Sheet '1 p l 16, 1929- B. E. G.-MITTELL 4 CONTROL FOR WIRELESS RECEIVING SETS laIIIlO'II'IER ELECTRICAL APPARATUS Filed No v.'l3 1924 4 Sheets-Sheet 2 April 1929- B. E. G. MITTELL 1,709,274

CONTROL FOR WIRELESS RECEIVING SETS AND OTHER ELECTRICAL APPARATUS Filed Nov. 13, 1924 4 Sheets-Sheet 3 April 16, 1929. E MIT-F LL 1,709,274

CONTROL FOR WIRELESS RECEIVING SETS AND OTHER ELECTRICAL APPARATUS Filed NOV. 13, 1924 4 Sheets-Sheet 4 I mum P tented Apr. 16 ,i1929.

UNITEDJST'AT'ES'PATENT OFFICE.

BRENGHLEY ERNES GEORGE MITTELL, OF 'I VER, ENGLAND TALKING MACHINE COMPANY, A CORPORATION'OF ASSIGNOR TO VICTOR NEW JERSEY.

CONTROL FOR WIRELESS'RECEIVING SETS AND OTHER ELECTRICAL APPARATUS.

Application filed-November 13 1924, Serial'No. 749,789, and in Great Britain December 5, 1923.

This invention relates to improvements 1n controls for wires receiving sets and other electrical apparatus, the object of the inven-' tion being to provide a single controlby means'of which the variable components of the apparatus may be adjusted as required simultaneously. In the case of a wireless receiving set for example the object is to provide means whereby the various components of the apparatus, such for example as condenser, inductances, couplings and the like may be adjusted as required simultaneously by means .ofa single control. I

As a general rule these various components of the apparatus are operated through separate control knobs, owing to the fact that, to give the required result, eachcompone'nt requires to be revolved through a different angle. In existing apparatus, where it has been proposed to effect simultaneously, by

means of'a single control, the adjustment of two or more variable components, it has been necessary to make one or more of the variable components of an unusual and complicated shape or design in order to give the result desired.

According to the present invention therefore, instead of attempting to match up all the electrical characteristics of the componcnts of a receiving set for example, I give to each the movement which it requires by means, such as cams or equivalent devices, actuated from a single control member and designed to impart to the components dissimilar or irregular rates of. movement. By this means it is made possible to graduate a control wheel uniformly with markings corresponding to wave lengths and to design all the components with great'mechanical and electricalsl'ability and of standard pattern, to employ valves of uniform characteristics and to ensure the supply'of correct voltages to the. filaments and anodes.

Further, according to the present invention, apart from a'separate tuning device for giving theaerial of a wireless receiving set a standard value once and for'all when the receiving apparatus is installed (though this will not be required. if a so called aperiodic aerial is used) ,only one control member will be used for tuning all or any of the components of the set and by the movement of this single control, through suitable means, the variable components will be moved simultaneously, so as to vary the electrical value of two or more components in predetermined relationsh1p to one another. A single control enables a spindle to be revolved, from which spindle the several variable components will be moved to the extent in each case required. By I these means for example one component'of the apparatus may be adjusted for the purpose of tuning while a second component is adjustedto an electrical value bearing a predetermined relationshipto the frequency to i which the apparatus is tuned.

The means employed for giving the desired movement to the several variable components are preferably cams adapted to be rotated by the movement of the control member. Thus a cam so rotated may move one member of a variable electromagnetic coupling relatively to the other member of said coupling While a second cam varies the electrical value of a second variable component such as a condenser.

It has also been found convenient, instead of using a single aerial inductance coil to operate over the whole wave length range which the apparatus is intended to cover, to

use a number of inductance coils which are brought into circuit with the aerial in turn, each of which is operative in conjunction with a single reaction coil for a portion of the whole wave length range.

It may happen that local conditions un der whicha set is being used are such that alterations in the standard setting of the reaction coil, for example, are required at some particular wave length settings.

If for example the set were installed near to one particular transmitting station fromwhich it was desired to receive,

the signals from that station would in the ordinary way be too strong. This may be by locally enlarging or coil actuating cam.

conveniently effected recessmgthe reaction the apparatus is tuned.

Fig. 1 is a plan view of the apparatus, the top plate upon which the various components are mounted being removed, but ts position shown in dotted lines.

Fig. 2 is an elevation arrow'A in Fig. 1.

in the direction of the detector valve 78, and two magnifying valves 79 and 80.

All components are shown in the same rela tive positions in all the figures and the same component is designated bythe same referings carried in three brackets 14, 15, 16 pro 9 plate 1 and cast integral with it.

by screws 26 (Figs. 1 and 2).

ence cipher throughout.

g 1 is the plateupon which the various compon'ents are mounted. 2 is a knurled-wheel integral with which is formed a p1n1on 3.

These "are rotatably mounted upon a bolt 4" which screws into abracket 5' mounted upon the plate.1 by screws 6. Another pinion 7 of the same size as pinion 3 and engaging therewith is rotatablymounted upon a pin 8 car- .ried on the bracket 5, and the pinion 7 also engageswitha toothed wheel 9 of large diameter (Fig. 2) which is mounted by'means of distance pieces 10 and screws llupon the rear face of a wheel 12. 1 The wheel 12 acts as an indicator and suitable markings are engraved upon its rim, suchas wavelengths and the 13 which is capable of rotation in three bear jecting downwards from the undersideof the An ebonite flange 17 is rigidly mounted upon the shaft 13 and carries f ur'circular bonit'e boxes 18,19, 20, -21' (Fig: 3). In these four boxes are carried four inductance coils having different inductances the total wave length range being divided into-four parts each accommodated by one of the four inductance coils. The two ends of each coil are brought out to corresponding insulated segmentsof a commutator mounted upon the face of the flange 17. Thus in Fig. 3 the two ends of the inductance, coil containedwithin the box 19 are connected to the segments 22 and 23 ..respectively. Contact is made with the segments by brushes 24, whichare fastened by screws to an ebonite block 25 which is in turn-fastened to the bracket. 141

"Rigidly fastened to the shaft 13 is also a toothed wheel 27 which engages with'another' toothed wheel 28 of the same size,'rigidly fixed to a shaft 29 which isrotatably-nmunted in bearings carried in the bracket 15 anda bracket 30 also projecting downward from plate 1 and cast inte 'ralw'ith. it. Upon the the shaft 29 are alsorigid y fastened two cam wheels, one of which, 31, willbe referred to as as the reaction cam wheel.

Rotatably mounted on the shaft 13 is a member 38 carrying two projecting arms 39 and 40 the arm 39 carrying at its extremity a roller 41 which bears upon the edge of the condenser cam wheel 31 and the arm 10 carrying at its extremity a toothed segment 12 attached to it by screws 43. This toothed segment 42' engages with a pinion 4 1 rigidly attached to a shaft 14 carrying the moving vanes 46 of a variable condenser 15, the condenser being so constructed that its capacity is proportional to the square of the angle of rotation of the moving vanes. Rigidly fixed to the condensershaft eta-is also a drum 47 having a groove 48around' its periphery, in

1. This spring 51 tends to return the moving vanes of the condenser to the-position of minimum capacity and to keep the roller 11 in contact with the condenser cam wheel 31. A bell crank lever 53 is rotatably mounted on a shaft1 5 1 which is fixed in the bracket 15 and in abracket55 which projects downwards from theplate 1 and is cast integral with it. One arm 56 of the lever 53 carries a roller 57 which bears upon the edge of the reaction cam wheel 32. The other arm 58 of the bell crank is fastened to the arm 58 by screws 60. The

toothed segment 59 engages with a pinion 61.

formedupona member 62- which is rotatably mounted on the shaft 13. The member 62 has formed upon it a drum 63 and an arm 64.

The drum 63 is provided, with a groove 65 around its periphery in which rests a chain 66 fastened'tothe-drum 63by a screw 67 and at its other end fastened to a helical spring 68 which is anchored. to the lug 52. The arm 6-1 carries-a cylindrical ebonite box 69which is fastened to it by'means of a screw 70, and

contains the reaction coil, the spring 68 tend lever 53 carries a toothed segment 59 which slot7l through which a portion of the graduated wheel 12' is visible. A portion of the knurled wheel 2 projects through another slot 71 the panel .71. The devic'etis adjusted.-totherequired wave length by turnuntiljtherequired valueis indicated on the panel.-

:The operation of the' above described apparatus is as followsz- We will consider the components to be in ing the knurled wheel 2 from right to left wheel 12- opposite to thearrow 72 on' the;

the relative positions shown in the drawings.

The knurled wheel 2 isturned from right to left in Figs. 1' and 6 (or counter-clockwise in the other figures). and the graduated wheel 12 together with the shaft 13, the ebonite flange 17 carrying the fourinductan'c'e coils from 500 to 1000- metres, is in circuit through its commutator"v segments .22, 23 and the brushes 24 and the condenser'45 is connected in parallel with it. The cam Wheels'31, 32

are rotated in the opposite direction to the shaft'13' (that isclockwise') through-the toothed Wheels 27 and. 28. The condenser" cam wheel 31,-acting upon the roller 41 causes the member-39 together with the toothed segment'42 to rotate in a counter-clockwise direction, thus turning thevanesof the con-y denser 45 in a clockwise direction or increasing the capacity. The-rate at which the capacity is increased'is' determined by the shape 'of the earns.

53 is being rotated in a clockwise direction by the reaction cam wheel 32, thus causing the reaction coil- 69-to revolve in a counter- ClOCkWlSB-dllECl'ilOIllIl an orbit about the shaft 13. Intheconst'ruction illustrated the reaction cam is so designed that the reaction c011 moves in the same 'dlrection as the 1nduc-- tance coil. which is in circuit but at a slightly less rate. The electromagnetic couplingbetween the reaction coil and the inductance coil is comparatively tight at the minimum wave length to which the particularv inductance coil is tuned,'and asthe wave length is increased so the reaction coupling is loosened.

When the knurled wheel 2 has been rotated so far that the rollers 41 and 57 have reached crcsts73 and74 respectively (Fig. 3) on the cam wheels 31-and 32,the commutator segments corresponding to coil 19. are on the point of'leaving contact with the brushes 24 and the set is tuned to the maximum wave length for this particular coil namely 1000 metres. A slight further rotation of the knurled wheel 2 now causes the commutator segments corresponding to coil 20, which may for example cover a range of wave lengths from 1000 to 2000 metres, to come into contact with the brushes 24, whilst the rollers 41 and 57 drop into hollows 75 and 76 in the cam wheels 31 and 32 respectively (Fig. 3),

thus causing the condenser vanes to fly back under the influenceof the, spring 51 to the position of minimum capacity, whilst the reactioncoil 69 is pulled back by the spring 68 to the position of maximum coupling with the coil 20 or such other relative position as is found to be suitable for the particular wave length setting.

I claim: v 1. In a device of the class described 1nclud- Meanwhile the bell crank lever ing a. variable electromagnetic coupling,

means for adjusting said coupling including a single control member, and means including a cam member operatively assoclated therewith adapted to move both members of said coupling at different rates relative to one another. 2. In a device of the class described including a variable electromagnetic coupling and" a tuning device, a control member, meansineluding a cam member actuated thereby for moving both members of said coupling at different rates relative to one another, and means including a second cam member actuated by said control member and adapted to vary the electrical value of said tuning device in predetermined relationship to thevariation of'said coupling. 3.'-In a device of the class described, a variable electromagnetic coupling including a pluralitypf inductance coils adapted to be used for given portions of the wave length range, means for successively insertlng said coils in circuit, a single reaction coil, means positioning said reaction coil so as to be coupled with thatinductance coil which is in circuit, and a unit con rol for said first named and second named means." i

4. In a device of the class described, a control member, a shaft actuated thereby, a plurality of inductance coils disposed-about said shaft and revoluble therewith, a reaction coil rotatably supported on said shaft and coupled with one of said inductance coils, and a cam member operatively associated With said shaft and adapted to rotate said reaction coil at a rate different from the rate of rotation of said inductance coils.

5. In a device of the class described, a control member, a shaft actuated thereby, a plurality of inductance coils disposed about said shaft and revoluble therewith, said coils being adapted to be used for given portions of the Wave length range, means for-successively insorting said coils in circuit. a reaction coil rotatably supported onsaid shaft and coupled with that inductance coil which is in circuit, and a cam member operatively connected to said shaft for rotating said reaction coil with said inductance coil but at a different rate, said cam being adapted to allow said reaction coil to return to starting po- "sition when the succeeding inductance coil is the wave length range, means for successively inserting said coils in circuit, a reaction coil rotatably supported on said shaft and coupled With that inductance coil which is in circuit, and a cam member operatively connect ed to said shaft for rotating said reaction coil with said inductance coil but at a different rate, the surface of said cam having portions corresponding to said inductance coils, said reaction coil passing from' control of one portionof said cam to-control of the succeed- 5 ing portion wh'enthe succeeding inductance coilis inserted 1n circuit.

7. In 'adevice'of the class described, a con--.

' trol m'ember, a shaft actuated thereby, a-plural-ity of inductance coils disposed about said inductance coil but at a different rate, the sur- -[face of said cam having portions corresponding to said inductance coils, said reaction coil ,passing'fromcontrol of one portion of said.

cam to control of the succeeding portion when thesucceeding inductance coil is inserted in circuit, and a second vcam member operatively connected to said shaft/for adjusting said tuning' device, said second cam surface having portions corresponding'to said inductance coils and adapted'to adjust said tuning dcvice so as to'produce a substantially progressive increase in wave length.

' 8. In a device of the class described, the

succession therewith, and a tuning device, of

thereby for adjusting said coupling and sai .tuning device in predetermined relationship .to the proper values for the wave length indicombinationwith a reaction coil, a plurality of inductancecoils adapted to be coupled in a control member, and cam means actuategcated by s' aid'controlmember,

"9. ln anelectri'cal apparatus for radio re ception, a plurality of variable components including a, variable coupling, a single control member, and adjusting means operatively" connecting said control member with said val riable components, said means being adaptadjust the other of said components at a varying rate in predetermined relation to the Variation of said coupling.

' 5o 10. In a radio apparatus, a plurality of variable components including a variable cou- 4 pling, and means for adjusting said components simultaneously but at varying rates, in cluding a single control member and cam means operatively connecting the latterwith said variable components, said cam means being adapted to move both members of said coupling at different and varying rates.

In testimony whereof I have signed my I name to this specification.

B. E. e. MITTELL;

'45 ed to move both members of said coupling at varying rates relative to one another and to 

